Backend engineer (Go · C#/.NET · TypeScript · C++) who builds correctness-critical systems and obsesses over what breaks in production — idempotency, concurrency, exactly-once semantics, and failure recovery — backed by real-database tests, race-checked CI, and ~88% coverage.
📍 Istanbul, Türkiye — remote / relocation-ready · ✉️ rewwernick@gmail.com · LinkedIn
| Project | Stack | What it proves |
|---|---|---|
| matchbox | C++20 | Header-only limit-order-book matching engine — strict price-time priority, ~8.6M orders/sec single-threaded, property + fuzz tested under ASan/UBSan CI |
| ledgerline | Go · Postgres | Idempotent double-entry ledger — exactly-once transfers, zero overdraft under concurrency, proven against real Postgres (incl. a deadlock I designed out) |
| cacheguard | C# · ASP.NET Core | Resilient API gateway — rate limiting, request coalescing, circuit breaker, stale-cache fallback so a flaky upstream never cascades into an outage |
| hire-bridge | TypeScript · Node | Idempotent integration service — HMAC webhooks, retry/backoff saga, dead-lettering, two-way drift reconciliation, append-only audit trail (~98% cov) |
| settlement-recon | Go | Deterministic payment settlement reconciliation — mismatch classification, strict CSV ingest, CLI + HTTP API, Docker, CI |
| droolcat-agent | Rust · Tauri | Desktop cockpit that drives the Claude Code CLI headless and renders its agents, tool calls, and code as live, navigable graphs |
Every one clones, runs, and tests locally — built to be discussed deeply in an interview, not just starred.
20+ additional backend/systems projects — distributed sharding & consistent hashing (shardlab), Postgres migration-safety linting (migrationsafe), secret scanning (repoguard), stream analytics with HLL/Count-Min (streamsketch), plus drone-simulation and physics backends.
Correctness under load · idempotency & exactly-once · failure recovery · clean API contracts · tests that prove the hard guarantees · CI that catches races.
METU Computer Engineering · national-level competitive programming.